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Plasma Volume Calculator

Health

Estimate plasma volume from height, weight, sex, and hematocrit using Nadler's formula. A standard reference calculation, not a clinical planning tool.

Reviewed by the thecalcu.com team · Last updated July 19, 2026

120210
30150
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Estimated Plasma Volume

2.46
Estimated Total Blood Volume
4.25

This calculator computes your Estimated Plasma Volume, Estimated Total Blood Volume from the values you enter.

Inputs
HeightWeightSexHematocrit
Outputs
Estimated Plasma VolumeEstimated Total Blood Volume

What is a Plasma Volume?

The Plasma Volume Calculator estimates plasma volume, the liquid, non-cellular portion of blood, from height, weight, sex, and hematocrit. It builds on Nadler's formula for total blood volume, then adjusts for the red blood cell fraction.

For the underlying blood volume calculation, see the Blood Volume Calculator.

Why Use a Plasma Volume Calculator?

Total blood volume and plasma volume are related but distinct figures, and calculating plasma volume requires an additional hematocrit adjustment step. This calculator performs both steps together instantly.

Who Should Use This Calculator?

  • Students of physiology or nursing learning how plasma volume relates to total blood volume.
  • Healthcare educators demonstrating the hematocrit adjustment step.
  • Researchers working with plasma volume reference calculations.
  • Anyone curious about how hematocrit affects the plasma-to-blood-volume relationship.

What Insights Does the Plasma Volume Calculator Give You?

The Estimated Plasma Volume is the headline result, showing the liquid portion of your estimated blood volume. The Estimated Total Blood Volume shows the underlying Nadler formula figure before the hematocrit adjustment is applied.

How to use this Plasma Volume calculator

  1. Enter your height in centimetres.
  2. Enter your weight in kilograms.
  3. Select your sex.
  4. Enter your hematocrit percentage.
  5. Read the Estimated Plasma Volume and Estimated Total Blood Volume instantly.
Show formula & methodology ↓Show less ↑

Formula & Methodology

Total Blood Volume is calculated using Nadler's formula (see the Blood Volume Calculator for details).

Plasma Volume = Total Blood Volume × (1 − Hematocrit %)

Worked example, a total blood volume of 5.25 L with a hematocrit of 42%:

Plasma Volume = 5.25 × (1 − 0.42) = 5.25 × 0.58 = 3.05 L

Frequently Asked Questions

What is plasma volume?
Plasma volume is the liquid, non-cellular portion of blood, calculated as total blood volume minus the fraction occupied by red blood cells (hematocrit).
How is plasma volume calculated?
The calculator first estimates total blood volume using Nadler's formula from height, weight, and sex, then multiplies that by (1 minus hematocrit as a decimal) to isolate the plasma portion.
Why does hematocrit matter for plasma volume?
Hematocrit represents the percentage of blood volume occupied by red blood cells, so subtracting that fraction from total blood volume leaves the remaining plasma (liquid) volume.
Is this calculator used for clinical fluid management?
No, this is an educational reference calculator only. Actual fluid management and plasma volume assessment must be determined by a qualified healthcare professional based on the complete clinical picture.
How does this relate to the Blood Volume Calculator?
This calculator builds directly on the [Blood Volume Calculator](/blood-volume-calculator/)'s Nadler formula estimate, adding a hematocrit adjustment to isolate the plasma-specific portion.
What is a typical hematocrit value?
Hematocrit typically ranges around 38-50% in healthy adults, varying by sex and individual factors, though your specific value should come from an actual blood test rather than an assumption.
Why would someone want to estimate plasma volume specifically?
Plasma volume is relevant in various physiological and research contexts, including understanding fluid distribution and certain medication dosing calculations that reference plasma volume specifically rather than whole blood volume.
What unit does this calculator use for the result?
This calculator expresses plasma volume in litres (L), the same unit used for the underlying total blood volume estimate.
Can plasma volume change over short periods?
Yes, plasma volume can shift relatively quickly due to factors like hydration status, posture, and other physiological changes, which is part of why hematocrit itself can fluctuate somewhat between measurements.
Is Nadler's formula the only way to estimate blood volume?
Nadler's formula is one widely referenced method; other formulas and direct measurement techniques also exist, though Nadler's remains one of the most commonly cited reference equations.
Also known as
plasma volume estimateblood volume minus hematocritplasma volume formulaPV calculator